Trade of threatened vultures and other raptors for fetish and bushmeat in West and Central Africa
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Trade of threatened vultures and other raptors for
fetish and bushmeat in West and Central Africa
R . B U I J , G . N I K O L A U S , R . W H Y T O C K , D . J . I N G R A M and D . O G A D A
Abstract Diurnal raptors have declined significantly in Introduction
western Africa since the s. To evaluate the impact of
traditional medicine and bushmeat trade on raptors, we ex-
amined carcasses offered at markets at sites (– stands W ildlife is exploited throughout West and Central
Africa (Martin, ). The trade in bushmeat (wild-
sourced meat) has been recognized as having a negative im-
per site) in countries in western Africa during –.
Black kite Milvus migrans and hooded vulture Necrosyrtes pact on wildlife populations in forests and savannahs
monachus together accounted for % of , carcasses com- (Njiforti, ; Fa et al., ; Lindsey et al., ), and it
prising species. Twenty-seven percent of carcasses were of is estimated . billion kg of wild animal meat is traded an-
species categorized as Near Threatened, Vulnerable or nually in Central Africa (Wilkie & Carpenter, ). In add-
Endangered on the IUCN Red List. Common species were ition to being exploited for bushmeat, many animals are
traded more frequently than rarer species, as were species hunted and traded specifically for use in traditional medi-
with frequent scavenging behaviour (vs non-scavenging), gen- cine, also known as wudu, juju or fetish (Adeola, ).
eralist or savannah habitat use (vs forest), and an Afrotropical The use of wildlife items for the treatment of a range of
(vs Palearctic) breeding range. Large Afrotropical vultures physical and mental diseases, or to bring good fortune,
were recorded in the highest absolute and relative numbers has been reported in almost every country in West and
in Nigeria, whereas in Central Africa, palm-nut vultures Central Africa. Birds, mammals, reptiles and other taxa
Gypohierax angolensis were the most abundant vulture spe- are sold at specialized fetish markets. However, many spe-
cies. Estimates based on data extrapolation indicated that cies are sold for fetish alongside those sold for their meat,
within West Africa % of carcasses were traded in Nigeria, or they are sold for either purpose, suggesting that the trad-
% in Benin and % elsewhere. Offtake per annum in West itional medicine and bushmeat trades are probably inte-
Africa was estimated to be –, hooded vultures, – grated and to some extent interdependent (Saidu & Buij,
palm-nut vultures, – Rüppell’s griffons Gyps rueppellii, ; Williams et al., ). In urban settings the commercial
– African white-backed vultures Gyps africanus, – trade in wildlife-based medicinal products is often concen-
lappet-faced vultures Torgos tracheliotos, and – crowned trated in traditional markets, where various animals, includ-
eagles Stephanoaetus coronatus. This represents a sizeable ing threatened species, are offered openly for sale. In a few
proportion of regional populations, suggesting that trade is countries such practices have become uncommon, but in
likely to be contributing significantly to declines. Stronger Burkina Faso and Benin they represent a strong cultural
commitment is needed, especially by governments in tradition that is supported by the governments of these
Nigeria and Benin, to halt the trade in threatened raptors countries (Nikolaus, ).
and prevent their extirpation. The commercialization of biological resources often has
important conservation implications for heavily exploited spe-
Keywords Bushmeat, commercial trade, diurnal raptors, cies, especially those under pressure from other anthropogenic
traditional medicine, vultures, West and Central Africa factors, such as habitat loss (Alves et al., ). This is the case
To view supplementary material for this article, please visit in many parts of West and Central Africa, where human
http://dx.doi.org/./S population densities and growth rates are high, even by
sub-Saharan African standards. Increases in human popula-
tions contribute to high rates of land-use change and exploit-
ation of wildlife, which also occurs frequently in protected
R. BUIJ (Corresponding author) Alterra, Wageningen University and Research
Centre, PO Box 47, 6700 AA Wageningen, The Netherlands areas in these regions (Brashares et al., ; Newmark,
E-mail ralph.buij@wur.nl ). Large, long-lived apex predators with low productivity
G. NIKOLAUS Feldweg 87, Cuxhaven, Germany and slow maturation rates, such as large raptors, are especially
R. WHYTOCK School of Biological and Environmental Sciences, University of vulnerable to increases in mortality rates, which can have a
Stirling, UK significant impact on population viability (Sæther & Bakke,
D. J. INGRAM School of Life Sciences, University of Sussex, Brighton, UK ). Given such vulnerability, increasingly intense persecu-
D. OGADA* The Peregrine Fund, Boise, Idaho, USA tion and hunting pressure related to commercial trade was
*Also at: National Museums of Kenya, Ornithology Section, Nairobi, Kenya suggested as one of the major drivers of the widespread de-
Received August . Revision requested December . cline of vultures (i.e. Rüppell’s Gyps rueppellii, white-backed
Accepted April . First published online August . Gyps africanus, lappet-faced Torgos tracheliotus, white-headed
Oryx, 2016, 50(4), 606–616 © 2015 Fauna & Flora International doi:10.1017/S0030605315000514
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https://doi.org/10.1017/S0030605315000514Threatened raptors in Africa 607
FIG. 1 Locations of the
markets in West and Central
Africa where surveys of raptor
carcasses for sale were
conducted during –
(Supplementary Table S).
Biomes are based on White
().
Trigonoceps occipitalis, and hooded vultures Necrosyrtes mon- component of traditional medicine in the region, we deter-
achus) in the savannah biome during – (Thiollay, mined the overall contribution of vultures to the total number
, ; Rondeau & Thiollay, ). Although a variety of raptor carcasses recorded, and examined temporal changes
of techniques are used to kill vultures and other raptors for therein. We also evaluated changes in the proportion of black
traditional medicine and consumption (Buij & Croes, ), kites Milvus migrans among carcasses, because these relative-
the use of poisoned baits is probably the most widespread ly common raptors are used regularly as substitutes for vul-
method, often killing many vultures in a single location tures by fetish traders, who pluck feathers from the kites’
(Mander et al., ; Saidu & Buij, ). heads so that they resemble hooded vultures (Nikolaus,
We evaluated the potential impact of the traditional medi- ). Vultures have become rare, and their parts more expen-
cine and commercial bushmeat trades on raptor populations sive, and therefore we expected that the contribution of black
in West and Central Africa, based on counts of raptor car- kites to carcass counts might have increased over the years.
casses offered for sale at market stands. We assessed the com- We estimated the numbers of raptors traded per annum, to
position of raptor carcasses offered for sale, and investigated assess the potential impact of the regional trade on threatened
the relationship between the numbers sold and morphologic- populations.
al and ecological characteristics of the species identified. Our
results were used to determine which species are most likely
to be vulnerable to the trade and in which regions and coun- Methods
tries. Based on previous studies we expected some taxa (e.g.
vultures) and heavier-bodied species to be represented at Market inventories
markets more frequently than other species (Nikolaus, ;
Williams et al., ). We also predicted that a species’ migra- Carcass counts were conducted at fetish and bushmeat mar-
tory status would influence its trade numbers. Afro– kets in the following countries throughout West and Central
Palearctic migrants spend – months of the year at northern Africa (Fig. ): Benin, Burkina Faso, Cameroon, Democratic
latitudes (with the exception of over-summering individuals Republic of the Congo, Equatorial Guinea, Gabon, Ghana,
of some species) and were expected to be represented less Ivory Coast, Mali, Niger, Nigeria and Togo. These included
commonly than Afrotropical resident species (i.e. those that our own counts conducted at intervals of one year or more
are present year-round in the region), including intra-African during – in eight West African countries and three
migrants. Controlling for species’ abundance, we expected Central African countries (Supplementary Table S). Our
scavengers and savannah species to be recorded more fre- data were supplemented by published and unpublished re-
quently than non-scavengers and forest species, which are as- ports of raptor carcasses recorded during surveys of bush-
sumed to be harder to kill (i.e. poison) and detect, meat markets in Cameroon, Equatorial Guinea and Gabon
respectively. As vultures are known to be an important during –. The latter counts were gathered from the
Oryx, 2016, 50(4), 606–616 © 2015 Fauna & Flora International doi:10.1017/S0030605315000514
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https://doi.org/10.1017/S0030605315000514608 R. Buij et al.
bushmeat database of the OFFTAKE project (OFFTAKE, vultures) were considered separately because they are particu-
), a collaborative project that collates datasets that larly highly valued by fetish traders and have undergone the
quantify the offtake of terrestrial species (e.g. from subsist- greatest declines in the region (Thiollay, ). Black kites
ence hunting, medicinal use, trophy hunting). Datasets for were considered separately because they are among the
the OFFTAKE database were gathered by searching the lit- most common raptors in the fetish trade and are known to
erature and contacting authors to request their raw data. be sold as substitutes for vultures. We also evaluated changes
Our surveys covered mostly fetish markets in West Africa in the proportional contribution of black kites and hooded,
and commercial bushmeat markets in Central Africa. palm-nut and large Afrotropical vultures among cumulative
Stands were visited throughout the year, covering the nor- counts of raptor carcasses in all West African markets during
thern winter and summer periods as well as the local dry –. Relative abundance of carcasses, rather than total
and wet seasons (Supplementary Table S). Individual counts, was evaluated because survey effort and recorded
stands were surveyed only once per year. A proportion of trade volumes varied between years. We used standard linear
the same stands were revisited in different years, although regression to investigate whether the proportions of these
relocation of stands and changes in ownership and stand raptors in counts varied between years. As necessary, data
numbers made it difficult to track individual stands were log -transformed to meet the criteria of normality
throughout the study period. For the same reason, the num- and homogeneity of variance.
ber of stands visited each year varied (Supplementary
Table S). Countries with larger, more numerous wildlife
markets (e.g. Benin, Nigeria) were visited more often and Characteristics of traded raptors
covered more extensively than countries where the trade
was limited (e.g. Ghana, Togo). The markets surveyed Covariate modelling was used to evaluate predictions that
were in villages and towns distributed over a wide geograph- total carcass counts for each species (i.e. the cumulative num-
ical area and were approximately equally distributed among ber of complete skins or heads counted) increased with spe-
forest (n = locations) and savannah, and forest–savannah cies’ abundance and body mass, and varied according to main
transition biomes (n = ; Fig. ), thus minimizing any site habitat, scavenging behaviour, phylogenetic position and mi-
(i.e. habitat) effect on species composition of the overall gratory status. The abundance of each species was taken from
sample. Some markets were visited more often than others, the most authoritative field guide for western Africa, from
however, and the largest markets in Benin and Nigeria in Mauritania in the north-west to Congo in the south-east
particular were located near or in the forest biome. In (i.e. overlapping with the study area and period of the
some countries, such as Nigeria, only a proportion of well- study; Borrow & Demey, ). Species were categorized ac-
known markets were visited, whereas most or all known cording to their abundance, as follows: scarce (encountered
markets were visited in other West African countries. only irregularly, and infrequently to rarely within its normal
Local interpreters assisted in locating markets and checking habitat), uncommon (encountered relatively frequently but
stalls. Carcasses were enumerated by observing and count- not regularly within its normal habitat), not uncommon (usu-
ing each raptor on display. Some birds were represented by ally, but not invariably, encountered within its normal habi-
entire carcasses, others merely by their heads; both are re- tat), common (or locally common; invariably encountered
ferred to here as representing a carcass. singly or in significant numbers within its normal habitat,
sometimes only locally). Information on the main habitat
(i.e. most commonly found (year-round): savannah, forest
Trade per country and region or both), migratory status and mean body mass was also
taken from the literature (Del Hoyo et al., ; Borrow &
The proportion of hooded and palm-nut vultures Gypohierax Demey, ; Ferguson-Lees & Christie, ). Egyptian vul-
angolensis, large-bodied (i.e. . kg) Afrotropical vultures, ture Neophron percnopterus, peregrine falcon Falco peregrinus
black kites and other diurnal raptors among total carcass and common kestrel Falco tinnunculus have Afrotropical and
counts was calculated, to evaluate differences between coun- Palearctic breeding ranges and were considered Afro–
tries (those with the largest markets: Nigeria, Benin) and re- Palearctic migrants based on the breeding range of the
gions (West and Central Africa). We treated palm-nut and majority of individuals in West Africa (Thiollay, ).
hooded vultures separately because they are both known to Because black kites were mostly yellow-billed kites (i.e.
be commonly traded (Nikolaus, ); the first is a largely fru- the Afrotropical race aegyptius, which outnumbers the
givorous, not uncommon vulture of wet savannahs and for- Palearctic race migrans in most of West and Central Africa,
ests, and the second is a locally common scavenger of apart from in the far west), the species was considered an
livestock carcasses, waste, faeces and other anthropogenic Afrotropical resident. Body mass was averaged for adult
offal in and around settlements. Large Afrotropical vultures males and females. With regard to scavenging behaviour,
(Rüppell’s, lappet-faced, white-backed, and white-headed species were categorized based on available information
Oryx, 2016, 50(4), 606–616 © 2015 Fauna & Flora International doi:10.1017/S0030605315000514
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https://doi.org/10.1017/S0030605315000514Threatened raptors in Africa 609
TABLE 1 Explanatory variables used to examine the number of carcasses per species of raptors sold for fetish or bushmeat in markets in
West and Central Africa (Fig. ) during –.
Covariate Description
Abundance Common, not uncommon, uncommon, scarce
Habitat Savannah, savannah & forest, forest
Functional group A Non-scavenger, frequent scavenger, obligate scavenger
Functional group B Non-scavenger, scavenger
Functional group C Obligate scavenger, other
Migratory status Afro–Palearctic migrant, Afrotropical resident
Body mass Mean body mass (kg) of adults
Phylogeny GYPINA Old World vultures (Aegypius, Gyps, Necrosyrtes, Torgos, Trigonoceps); ACCIPITRINA
booted and hawk eagles, sparrowhawks, chanting goshawks, harriers, African fish eagle, black kite,
buzzards, bat hawk (Aquila, Hieraaetus, Lophaetus, Polemaetus, Stephanoaetus, Accipiter, Melierax,
Micronisus, Circus, Haliaeetus, Milvus, Buteo, Butastur, Kaupifalco, Macheiramphus); FALCONIDAE
falcons (Falco); GYPAETINI Pernine kites, gymnogene, Old World vultures (Aviceda, Pernis,
Polyboroides, Gypaetus, Neophron); CIRCAETINA snake eagles (Circaetus, Dryotriorchis); OTHER
elanine kites, secretary bird, osprey (Elanus, Chelictinia, Sagittarius, Pandion)
on their diet composition in sub-Saharan Africa (e.g. Brown & obligate scavenger, () frequent scavenging (i.e. without dif-
Amadon, ; Steyn, ; Mundy et al., ; Ferguson-Lees ferentiation between obligate and frequent scavengers), or
& Christie, ): non-scavenger (including species that scav- () obligate scavenging. Support for the latter would indicate
enge only rarely or occasionally), frequent scavenger (sca- that obligate scavenging drives carcass abundance patterns,
venges frequently but also consumes a significant whereas support for the second subdivision would suggest
proportion of live prey; palm-nut and white-headed vultures, that abundance patterns were driven by frequent scavenging.
tawny eagle Aquila rapax, black kite, Eurasian marsh harrier We used the corrected Akaike information criterion (AICc)
Circus aeruginosus, bateleur Terathopius ecaudatus), and ob- value to select the most parsimonious models (those that fit
ligate or near-obligate scavenger (Rüppell’s, lappet-faced, the data best with the fewest parameters; i.e. with the lowest
white-backed, hooded, Egyptian vultures). Unlike other Old AICc; Burnham & Anderson, ), and the top four ΔAICc
World vultures the white-headed vulture was not categorized of models as the cut-off criterion for delineating a set of top
as an obligate scavenger because it is likely to consume live models. We computed model-averaged parameters by aver-
prey regularly (Murn, ). The Eurasian marsh harrier fre- aging over all models in the set of top models. We used the
quently scavenges in the European part of its winter range dredge function in R (part of the package MuMIn v. ..;
(e.g. Hiraldo et al., ) and this is also likely to be the case Bartoń, ) to implement a model-averaging approach for
in the Sahel (Zwarts et al., ). We used results of phylogen- the top models to make robust parameter estimates and pre-
etic analyses based on nuclear and mitochondrial DNA to dictions (Johnson & Omland, ), and estimated the rela-
classify raptor species into six groups (Lerner & Mindell, tive importance of each variable, based on the sum of Akaike
; Griffiths et al., ; Table ). weights. We subsequently evaluated the effect of variables
We used generalized linear models with a negative bino- based on overlap of the % confidence intervals (following
mial distribution and log link function using the package Burnham & Anderson, ).
MASS in R v. ... (R Development Core Team, ) to
model how explanatory variables describing the various spe- Total numbers involved in the trade
cies characteristics (Table ) affected total carcass counts per
species, summed across all the data, including across years To determine the potential impact of the trade on raptor po-
and across all sites. Habitat, functional group, phylogeny pulations, we estimated the number of raptors traded annu-
and status were included as categorical variables, abundance ally at West African markets during –, using
as an ordinal variable and body mass as a continuous vari- extrapolation of mean counts per market stand and
able. We explored three sets of models, each consisting of known carcass turn-over rates. These estimates were based
all possible subsets of combinations of explanatory variables, on carcass counts at stands visited in , stands in
including one of three explanatory variables for functional , stands in , stands in , and stands in
group (Table ). By including three subdivisions for the func- , in Benin, Nigeria, Mali and Burkina Faso. Because spe-
tional group variable in each model set, we examined the rela- cies composition varied between Nigeria and Benin we cal-
tive support for each of three alternative hypotheses: that culated mean counts per stand separately for these and the
species carcass counts are best explained by () an increasing remaining countries, and extrapolated to the estimated total
frequency of scavenging, from non-scavenger, to frequent, to number of stands. In Nigeria we visited approximately
Oryx, 2016, 50(4), 606–616 © 2015 Fauna & Flora International doi:10.1017/S0030605315000514
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https://doi.org/10.1017/S0030605315000514610 R. Buij et al.
one-third of the market stands trading in animal parts in
, and therefore we tripled the number of stands to de-
rive a country-wide estimate of stands. We estimated a
total of stands for Benin and for the remaining West
African countries where surveys had been conducted. We
cautiously estimated the minimum and maximum numbers
traded based on turnover rates of two to three birds per
stand per year, although detailed examinations for various
species suggest that this turnover rate can be higher (–
or more carcasses per year; Cocker, ; Nikolaus, ;
Awoyemi, ; G. Nikolaus, unpubl. data).
FIG. 2 Percentages of black kites Milvus migrans, large
Afrotropical vultures (Rüppell’s Gyps rueppellii, lappet-faced
Results Torgos tracheliotos, white-backed Gyps africanus, and
white-headed vultures Trigonoceps occipitalis), palm-nut
Trade per country and region Gypohierax angolensis and hooded vultures Necrosyrtes
monachus, and other raptors among raptor carcasses recorded at
Black kite and hooded vulture together represented % of a markets in Nigeria (n = carcasses), Benin (n = ,), Mali,
total , raptor carcasses of species recorded at markets Togo, Niger, Ivory Coast, Ghana and Burkina Faso (n = ),
and Cameroon, Equatorial Guinea, Gabon and DRC (n = )
in West and Central Africa (Supplementary Table S).
during –.
Shikra Accipiter badius was the most commonly traded small
raptor, comprising .% of the total carcass count. Afro–
Palearctic migrants together represented .% of carcass during – (linear regression: F, = .,
counts. This is assuming that short-toed Circaetus gallicus β = . ± SE ., P = ., adjusted R = .). However, sur-
and Beaudouin’s snake eagle Circaetus beaudouini carcasses veys in may not have yielded a representative sample be-
were divided equally between species, and excluding the cause a relatively small number of carcasses was recorded
(likely) possibility that the Palearctic race migrans of black (n = ) compared to other years (n = –). Excluding
kite comprised a small proportion of black kite carcasses. from the analysis, a significant proportional increase of
The most common Afro–Palearctic migrant among carcasses black kites over the years was apparent (linear regression:
was the Eurasian marsh harrier. Palm-nut and Rüppell’s were F, = ., β = . ± SE ., P = ., adjusted R = .;
the most commonly recorded vultures, after the hooded vul- Fig. ), providing support for the idea that black kites have
ture. However, the contribution of vultures to total carcass been traded increasingly since the late s. No significant
counts varied between countries and regions (Fig. ); whereas temporal trend was detected in the proportion of large
the greatest proportion and diversity of large Afrotropical vul- Afrotropical (F, = ., β = −. ± SE ., P = ., ad-
tures (Rüppell’s, white-backed, white-headed, lappet-faced vul- justed R = −.), palm-nut (linear regression on
tures) were recorded in Nigeria (%; n = carcasses), log -transformed data: F, = ., β = −. ± SE .,
relatively few were offered for sale elsewhere in West Africa P = ., adjusted R = −.) or hooded vultures (F, = .,
(.%; n = ,). In Central Africa palm-nut vulture carcasses β = −. ± SE ., P = ., adjusted R = −.) among
were recorded most commonly (% of total counts; n = raptor carcasses.
carcasses), contrary to the situation in West African countries
(–% of carcasses). Overall, % of carcasses on offer were of Characteristics of traded raptors
species categorized as threatened (Near Threatened to
Endangered) on the IUCN Red List of Threatened Species Our models found strong support for an influence of spe-
(IUCN, ). Of these (n = ), % were found in Nigeria cies’ abundance, habitat, migratory status, and scavenging
and % in Benin. Nigeria was the only country where the re- behaviour on carcass counts. All six plausible models (i.e.
gionally threatened martial eagle Polemaetus bellicosus and sec- models with ΔAICc , of the top model; Table ) included
retary bird Sagittarius serpentarius were recorded at markets the influence of species’ abundance and scavenging behav-
(Supplementary Table S). Despite more than half of markets, iour, and five and four of the six top models featured habitat
including some of the largest markets, being located in the for- and migratory status, respectively. Body mass was repre-
est biome, % of carcasses were of species mainly associated sented once in the top model set, and phylogeny and func-
with savannah habitats, suggesting that raptors are transported tional group C were not included. The four most important
significant distances to commercial markets. predictors among the six plausible models, in decreasing
The data did not indicate a significant increase in the pro- order of importance, were species’ abundance (relative im-
portional contribution of black kites to total carcass counts portance: ), habitat (.), functional group B (.), and
Oryx, 2016, 50(4), 606–616 © 2015 Fauna & Flora International doi:10.1017/S0030605315000514
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https://doi.org/10.1017/S0030605315000514Threatened raptors in Africa 611
–, white-backed vultures, –, lappet-faced
vultures, and – crowned eagles Stephanoaetus coro-
natus. For –% of species (n = ) , individuals
are estimated to be traded annually in West Africa.
Discussion
The diversity of raptor species, and number of individuals,
offered at West and Central African markets, particularly in
Nigeria and Benin, is considerable. Approximately % of
the region’s diurnal raptor species were on sale, suggesting
FIG. 3 Linear regression model of the relationship between the
that many raptors are used as fetish species (Nikolaus, ,
percentage of black kites among raptor carcasses at markets in
West and Central Africa (Fig. ) and year of survey, during ; Williams et al., ) as well as bushmeat (Saidu & Buij,
–. ; Buij & Croes, ; Whytock et al., ).
Our results indicate that Nigeria and Benin are import-
status (.; Table ). The model-averaged parameters of the ant drivers of the regional trade in raptors in West Africa.
top models (Table ) strongly supported the hypothesis that This supports an earlier assertion by Nikolaus () that
more common species were represented more often among there is a high per capita use of raptors for fetish in
carcasses than scarcer species. Forest species were less likely Nigeria and Benin. Fetish demand and prices of vultures
to be found in markets than savannah species, or habitat are particularly high in Nigeria (Nikolaus, ), where
generalists that inhabit both savannah and forests (Fig. ). large Afrotropical vultures constituted a greater proportion
Scavenging behaviour increased the probability of being of raptors traded compared to Benin or elsewhere in West
traded compared to non-scavenging (Fig. ) but there was and Central Africa. Large Afrotropical vultures were already
little support for the idea that obligate scavenging alone largely extirpated in Nigeria in the early s (Nikolaus,
was responsible for this pattern (functional group C fea- ), and human-commensal hooded vultures have de-
tured only twice among models with AICc weights $ %; clined (Ogada & Buij, ). The diversity and number of
Table ). Rather, our results strongly suggest that all species vultures for sale in Nigeria support anecdotal evidence
that scavenge frequently (i.e. frequent and obligate scaven- and results of questionnaire surveys indicating that the
gers) are traded more commonly than those that consume catchment area for Nigerian traders extends at least from
carrion only rarely or occasionally (Table ). Species with Burkina Faso to Chad (Nikolaus, ; Saidu & Buij, ).
an Afrotropical breeding range were more likely to be traded Because large Afrotropical vultures or their eggs are valued
compared to those with a Palearctic breeding range (Fig. ). at several months’ salary, Nigerian poachers invest in ob-
Although body mass featured in the top model set (relative taining them, sourcing them from countries in the wider re-
importance: .; Table ), the confidence intervals of the gion (Saidu & Buij, ). Shifts in pressure to other species,
body mass predictor included zero, suggesting species’ such as migratory black kites, suggest that the trade has the
body mass did not influence carcass counts. potential to affect raptor populations beyond West and
Central Africa.
For many West and Central African raptors the impact of
Total numbers involved in trade the trade may be limited compared to other anthropogenic
and climate-related factors that influence their food re-
In West Africa during – an estimated ,–, sources, nest availability, and population dynamics (e.g.
raptors were traded each year, based on extrapolated carcass Buij et al., a,b). The commercial trade, however, can be
count data (Supplementary Table S). An estimated – implicated in the decline of vultures and other large raptors
, raptors were traded each year in Benin, ,–, in the region. For some species, such as Rüppell’s, hooded,
in Nigeria, and – in the rest of West Africa white-backed, white-headed, and lappet-faced vultures, the
(Supplementary Table S). The bulk of the trade was in numbers traded probably represent a significant proportion
Nigeria (% of carcasses), with % in Benin and % else- of their regional populations. Although rigorous population
where in West Africa. Assuming turn-over rates of – indi- estimates are unavailable for most species, the extrapolated
viduals per stand per year, an estimated ,–, hooded annual toll of lappet-faced vultures in West Africa during
vultures and ,–, black kites were traded during the – represents as much as .–.% of c. , indivi-
-year period in West Africa. Estimates for other commonly duals estimated to have occurred in West Africa and the
traded large raptors during this period were ,–, Sahara during the s (Shimelis et al., ), assuming
palm-nut vultures, ,–, Rüppell’s vultures, they were all sourced from this region. However, trade
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TABLE 2 Top generalized linear models (Akaike weight . %) examining the relationship between cumulative carcass counts of raptor
species (Supplementary Table S; n = , carcasses) at markets in countries in West and Central Africa during – (Fig. ) and
the species’ abundance, habitat, functional group, phylogenetic position, body mass, and migratory status (Table ), with degrees of free-
dom, corrected Akaike information criterion (AICc), ΔAICc and Akaike weight.
Model1 df AICc ΔAICc Akaike weight2
Abundance + habitat + functional group B + status 9 434.51 0.00 0.31
Abundance + habitat + functional group B 8 435.91 1.39 0.15
Abundance + functional group B + status 7 437.32 2.81 0.08
Abundance + habitat + functional group A + status 10 437.39 2.88 0.07
Abundance + habitat + functional group B + body mass + status 10 437.45 2.94 0.07
Abundance + habitat + functional group A 9 438.22 3.70 0.05
Abundance + habitat + functional group B + body mass 9 438.78 4.27 0.04
Abundance + functional group B + body mass + status 8 439.29 4.78 0.03
Abundance + functional group B 6 439.79 5.27 0.02
Abundance + habitat + functional group A + body mass + status 11 439.88 5.37 0.02
Abundance + functional group A + status 8 440.11 5.60 0.02
Abundance + habitat + functional group C + status 9 440.16 5.64 0.02
Abundance + habitat + functional group C 8 440.28 5.76 0.02
Abundance + habitat + functional group B + status + phylogeny 14 441.12 6.61 0.01
Abundance + habitat + functional group A + body mass 10 441.17 6.65 0.01
Abundance + habitat + functional group B + phylogeny 13 441.23 6.72 0.01
Abundance + functional group A + body mass + status 9 441.33 6.81 0.01
Abundance + habitat + body mass 8 442.00 7.49 0.01
Abundance + functional group A 7 442.33 7.82 0.01
Abundance + functional group B + body mass 7 442.36 7.84 0.01
Abundance + habitat + body mass + status 9 442.48 7.97 0.01
Abundance + habitat + status 8 442.68 8.17 0.01
Null 2 497.20 62.69 0.00
Listed in order of most to least parsimonious model, after fitting combinations of all possible subsets with each of the three explanatory variables for func-
tional group.
The weight of evidence in support of the model (cf. Burnham & Anderson, )
volumes may have constituted a higher proportion of popu- even with only a small decrease in adult survival rates
lations remaining in –, as was the case for the white- (Whitfield et al., ; Oro et al., ; Ortega et al., ).
headed vulture. There were an estimated , or more Assuming the majority of vultures and other large raptors on
white-headed vultures in West Africa in the s (Mundy offer at markets were killed specifically for trade, the trade
et al., ), and .–.% of this number were channelled probably contributed to increased mortality rates and signifi-
through the trade each year during –. As the most cant population declines, including the % decline of large
recent estimate suggests that as few as remained in vultures outside protected areas in central West Africa during
(C. Murn, unpubl. data), the annual trade constituted .–% – (Thiollay, ).
of the remaining West African population. Hooded vultures, The percentage of vultures among raptor carcasses was
which are under pressure from poachers, were estimated to highest in Central Africa, mostly accounted for by palm-nut
number c. , individuals in West Africa (Ogada & vultures. The palm-nut vulture is an important and valuable
Buij, ). Our estimates suggest that .–% of those were species for fetish purposes in West Africa, and individuals
lost to the trade annually during –. Our estimates have been sold for c. USD in Nigeria (Nikolaus, ).
of annual tolls, even those based on more recent population We estimated its offtake in West Africa to be – indi-
estimates, are likely to be biased low because we used conser- viduals per annum (i.e. .% of the continental population
vative estimates of turnover rates to estimate numbers traded; of c. ,, most of which are in West and Central Africa;
other studies suggest these may be significantly higher (e.g. Mundy et al., ). However, the true impact of hunting
Awoyemi, ). Although we lack quantitative data, the ma- on palm-nut vulture populations may remain largely con-
jority of raptors recorded at markets appeared to be adults, cealed, at least in Central Africa, where the vultures are
which have a vital role in population dynamics, especially often consumed in bushmeat hunting camps rather than
for larger species (Sæther & Bakke, ). Persecution may being transported to markets (Whytock et al., ).
be one of the most important factors of non-natural mortality Although this highly prized species is categorized as Least
in threatened populations of large raptors, which may decline Concern on the IUCN Red List (IUCN, ) because of
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https://doi.org/10.1017/S0030605315000514Threatened raptors in Africa 613
TABLE 3 Effects of species characteristics assumed to influence cumulative carcass counts of raptor species (n = , carcasses) at mar-
kets in countries in West and Central Africa during – (Fig. ), with model-averaged parameter estimates for each variable
(Table ) in the six most strongly supported models (Table ), and the relative importance of explanatory variables.
Variable Parameter estimate (95% CI) Relative importance1
(Intercept) 3.59 (2.38–4.81)
Abundance2
Not uncommon −1.35 (−2.11 – −0.60) 1.00
Uncommon −2.53 (−3.22 – −1.84)
Scarce −3.50 (−4.69 – −2.31)
Habitat3
Savannah 0.97 (0.21–1.73) 0.90
Savannah & forest 1.46 (0.59–2.32)
Functional group B4
Scavenger 0.95 (0.38–1.52) 0.83
Status5
Afrotropical resident 0.66 (0.07–1.25) 0.72
Functional group A4
Frequent scavenger 0.80 (0.11–1.50) 0.17
Obligate scavenger 1.08 (0.32–1.84)
Body mass −0.03 (−0.19–0.13) 0.10
Calculated by summing Akaike weights across the top model set (Burnham & Anderson, ); % confidence intervals of the estimate not overlapping
zero are indicated in bold.
Reference group: common
Reference group: forest
Reference group: non-scavenger
Reference group: Afro–Palearctic migrant
its large range, population size and apparently stable popu- particularly commonly traded, whereas trade in forest spe-
lation, ongoing persecution warrants closer examination of cialists is comparatively uncommon. This relative scarcity
its population trends. of forest-restricted species in the trade may be related to
Other large raptors vulnerable to persecution include the difficulty in finding, shooting or poisoning these species,
Africa’s largest eagles (martial and crowned). Extrapolation which are generally more elusive. The greater numbers of
of the estimated annual toll suggests at least crowned ea- Afrotropical residents in the trade, including intra-African
gles were traded commercially in West Africa during – migrants, is probably related to their year-round availability;
, which represents an unknown but probably significant the majority of Afro–Palearctic migrants spend much of the
proportion of regional populations. Although these uncom- year outside the poachers’ catchment area.
mon raptors are unlikely to be poisoned on a scale compar- Our models support the hypothesis that, together with
able to scavengers, they may be shot; crowned eagles may be obligate scavenging vultures, raptors that scavenge frequent-
lured by bushmeat hunters imitating the calls of prey animals ly are more likely to end up at markets compared to non-
(Whytock & Morgan, ). This may occur more frequently scavenging species. We suspect this is related to the ease
than previously thought, as crowned eagles were the second of killing most scavengers using poisoned baits, which is
most common forest species and the commonest large rap- probably the most widespread method used to kill raptors
tors (i.e. . kg) recorded at markets after Rüppell’s, white- and other predator populations in sub-Saharan Africa
backed and lappet-faced vultures. Their slow maturation rate (Ogada, ). Frequent use of human-dominated, low-
and biennial reproduction in tropical forests make the quality habitats may increase the vulnerability to poisoning
crowned eagle one of the most vulnerable raptors to direct of some obligate and frequent scavengers (black kite,
persecution (Shultz, ; Whitfield et al., ), com- hooded vulture; Otieno et al., ; Kendall, ; Buij
pounding negative impacts of habitat loss and degradation, et al., a). Some frequent scavengers (black kite,
disturbance of nest sites, and prey depletion by bushmeat Eurasian marsh harrier) congregate at easily detectable
hunters (Lindsey et al., ; Whytock et al., ). roosts, possibly increasing their vulnerability to poachers;
The positive relationship between species’ abundance and the high search efficiency of others (bateleur, tawny eagle;
carcass counts suggests that at a regional scale species are tar- Kendall, ; Kane et al., ) may facilitate poisoning
geted indiscriminately to supply the trade. However, our re- or trapping using baits. Alternatively, some frequent scaven-
sults showed that Afrotropical habitat generalists inhabiting gers may constitute bycatch of poachers targeting more
forests and savannahs, and those of savannah habitats, are highly prized vultures.
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https://doi.org/10.1017/S0030605315000514614 R. Buij et al.
FIG. 4 Plots of the modeled relationship between carcass counts of raptor species and the species’ (a) abundance, (b) habitat, (c)
functional group B, and (d) status (Table ), as estimated by the top model (cf. Table ). Carcass counts are plotted on their original
scale. The black horizontal line represents the model-predicted value, with all other variables set to their most common category, and
the shaded areas indicate % confidence bands; the vertical ticks indicate number of observations.
It is possible that not all raptors recorded at markets therefore assume that the majority of raptors on offer at
were killed for trade; casualties related to other anthropo- markets are probably killed deliberately for the trade,
genic factors (e.g. electric power lines, roads, pesticides), or which is supported by information obtained from traders
disease may also be sold in markets. However, indirect in Nigeria (Saidu & Buij, ).
evidence suggests that mortalities related to these factors The trade in raptors for traditional medicine or for food is
probably account for only a small proportion of raptors of- likely to have contributed considerably to the significant de-
fered at markets. The electrical power transmission system cline of vultures and other large raptors, and possibly also to a
over most areas in West and Central Africa is poorly de- number of smaller raptors, in West and Central Africa.
veloped, unlike in North and southern Africa, where this is Within West Africa, Benin and Nigeria collectively accounted
a significant cause of mortality (Nikolaus, ; Jenkins for % of the carcasses traded during –.
et al., ). There are unlikely to be many raptor deaths Conservation efforts focused on these two countries would
caused by road traffic given the condition of most roads therefore have the most significant impact on curtailing this
prevents driving at high speed, which is confirmed by trade within the wider region. More than a quarter of raptors
generally few raptor carcasses found along roads (R. Buij, sold at the markets surveyed in West and Central Africa since
pers. obs.). Casualties from secondary pesticide poisoning are categorized as threatened on the IUCN Red List
also appear to be generally low, being significant only (IUCN, ), including five Afrotropical vultures that war-
when colonies of red-billed quelea Quelea quelea are rant uplisting to Critically Endangered on the basis of popu-
sprayed with fenthion when irruptions occur (Keith & lation decline (Ogada et al., ). A lack of population data
Bruggers, ). Deaths of hooded vultures as a result of makes it difficult to conduct accurate Red List assessments for
avian influenza may be significant, at least locally as some vulnerable species that are commonly exploited by the
shown in Burkina Faso (Ducatez et al., ), but we are trade (palm-nut vulture, crowned eagle). Increasing prices are
not aware of similar die-offs elsewhere in the region. We leading to increasing pressure on remaining vultures, as
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https://doi.org/10.1017/S0030605315000514Threatened raptors in Africa 615
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performance of the grasshopper buzzard (Butastur rufipennis) in a
played openly in markets suggests that their declining popu-
natural and a human-modified West African savanna. The Condor,
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for Statistical Computing. R Foundation for Statistical Computing, Habitat and Status. He performed most of the market surveys
Vienna, Austria. presented here. R O B I N W H Y T O C K ’s research interests include inves-
R O N D E A U , G. & T H I O L L A Y , J.M. () West African vulture decline. tigating the decline of Afro–Palearctic migrants, and the conservation
Vulture News, , –. ecology of birds in the Lower and Upper Guinean forests. D A N I E L
S Æ T H E R , B.E. & B A K K E , Ø. () Avian life history variation and I N G R A M is a conservation scientist and modeller investigating the ex-
contribution of demographic traits to the population growth rate. ploitation of terrestrial species throughout the tropics. He is the man-
Ecology, , –. ager of the OFFTAKE database. D A R C Y O G A D A is a conservation
S A I D U , Y. & B U I J , R. () Traditional medicine trade in vulture parts biologist whose main focus is East African raptors and combating poi-
in northern Nigeria. Vulture News, , –. soning of wildlife.
Oryx, 2016, 50(4), 606–616 © 2015 Fauna & Flora International doi:10.1017/S0030605315000514
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